Telephone system



C. S. RHOADS July 3, 1945.

TELEPHONE SYSTEM 2 Sheets-Sheet l Filed May 5, 1944 owoconnou on a on no one oauoooouo oooonooouo o o a o oo uuocouooo oooooaaooo o o o o c o o u 0 00000000 0 cnoocooouc o oo ooocooco NGWAN \G 55inc ooocooouoo INVENTOR C. S. Rh oads BQMS 53% July 3, 1945., & 'RHOADS 2,379,456

' 'IELEPHONE SYSTEM FiledMay 5, 1944 2 Sheets-Sheet 2 2?) Connectar 8 16 III-Signal at tel-Office w j INVENTOR I C. S, Elana/01s Patented July 3, 1945 g I .1 a 2,379,45

t t TELEPHONE SYSTEM Charles'Stanley Rhoads, Albany,.N. Y., assignor. t to American Telephone and. Telegraph Com-1; 4 pany, a corporation of New York 1944,'Serial No. 534,273 i Application- May .5,

. .5 Claims! (01. 15191-227).

Thisinvention relates-t telephone systems and, more particularly, to telephone machine-switching type.- a

It-often happens, due; for example, to directory errors; or to a subscriber moving away from a locality, that calls coming in for his former hum-- ber *niust be intercepte'd by an" op'erator so --that the calling party can be informed that-such a subscriber is not to be reached at such a number. It one of the primary objects :of this invention to provide arrangements for furnishing'an intercept serv'ice of this type. The arrangements of the-invention areparticularlyadapted' for use at unattended exchanges utilizing machine-switching equipment whichexchanges would be connected to anoffice having attentlantsi Anexample of an exchange of this type would be a community dial office which is usually" an office serving a small community by rn'eansof step-by-step;

panel or cross-bar machine sWitching equipment and normally having no attendants.-' The'comr'nunity dial type of office would'be connected with a so-called master office in anotherlocality which would have attendants. "With the'arrangernents of the invention, a call originating either at the master oflice orat the community dialofiice and intended for a number at the community dial oifice, may 'be intercepted by anattendant at the master oiiice. In the community dial type of ofiice the lines are usually multi-partylines hav ing a number of subscribers connected thereto. It

iscne of the featuresof the arrangements of this inventionv that a call intended for a'particular one of the subscribers ona multi-party line may be intercepted without interference to the other subscribers 0n the line. Other objects and fea the detailed description thereof hereinafter "given.

The invention may be more fullyunderstood from the'following description together twith the accompanying drawings, in the Figur'esl and 2 of which the invention is illustrated: Figure l sfa circuit diagram illustrating a preferre form of the invention. Fig. 2 isa circuit diagram showing in detail a part of the arrangements shown in Fig. :1 Similar reference characters have been used. to denote like parts in both of the figures. Inthe drawings are shown a number of trunks systems of thetures of the invention will appearmore fully-from such as L1 and L2 which would connecta master office, which is the type of ofiice which would haye' attendants, with an unattended 'offi'ce, such,; for example. as a. community dial office At the. master ofiice is shown a subscribers set i. .Let it. be asiumed that the subscriber. having this set-wishes to call a subscriber at thecommunity dial cfiice. v At the community dialfoffice is' shown a telephone line which is. a multi party; line and would have a number of subscriberst-{setslcon-' nected thereto. Onlythe ringing apparatus such as 46, 41, t8 and 49 of these sets is illustrated.

Let it'be assumed that the subscriber at-the masterf ofiice wishes to call" the set having. the ring ing apparatus lll' The subscriberatthe master office would give the calledsubscribers number to the operator at the master officer-Let it be assumed that 'tl"ne m'1mber, for purposes of illustration, would be 2734; "The oper'a'wr at "the masteromce through trunk equipment 3 would' con-'- meet the" subscriber to the trunk Li, and trunkequipment 4-a't the community dial office would connect this trunkto'a select'or"'5." The-selector' 5 would mum iadial tone 'to thefoperatorrat thefmaster office an'dfs'he'would *plug dialin'g equipment into'the jack- 6 and'c'ommence to'dial the number 2734.". The first-group: Oftwodieil impulses would cause the; switch of the step-byste'p selector to movef'to its 'secondlevel' of terminals' and huntuntil an idle "trunk suchas' 1 was-found leading to the-connector 8; The

arrangements to'be described later. I

. For the purposes of illustrating this invention, it will be assumed that the called subsr'zribers' set having; the ringing app ratus 49 is no flonger 'in use and'thatj calls for such a se't' are to'b'einter cepted. 1 To interceptsuch 'a-"call thecircuit 9 will be ,connected to 'a circuit] 0' and thence to aicircuit- 50' which leads to another "connector 21.. Thecircuit Swill alsoiibe ccnnectedto an intercept t runk,,43', the 'operationfof whichwill be described "in' more detail hereinafter; 'When the circuit"?! is'seized atftheconnector Bithe' v particular, code signal 'for' the subscriber having the ringing apparatus 49 will be transmitted" to theintercept trunk 43 and wil cause a 'groundt'd be place c l on conductor; H01: 7 This will complete the fol lowin'g circuitffromground, conductor H0;

winding ofrelay [06;armature'andbreak contact I of relay lllfi, conductor l I l winding offreIay I01; to battery and-ground. This'w ill operatefrelays 10.6 and'llql and they willlock upover thefol lowing. circuit: from ground'applied tothe sleeve of line 9;;when it was seized b'y'the connector,

conductorijl l2 j lower armature and make "c'ontact vof relay l llfi winding of relay 106; upper armature of relay lfl6, conductor H3, armaturefof relay'lpl, winding of relay 101 to battery and ground. The operation of relay I06- will connect the tip and ring conductors of circuit 9 to the tip and ring conductors of circuit ID. The operation of relay I01 will place a ground on conductor I6. This will actuate the relay ll. Before the relay I! is operated ground is applied to the ring side of the trunk L2 and the negative pole of battery I 8 is connected to the tip side of the trunk L2. At the master ofiice the midpoint of resistance I9 is connected to the grid of a vacuum tube 20. Due to the connection of'battery Hi to the trunk, a negative bias will be applied by battery I8 to the grid of the vacuum tube 20 and it will be maintained in an inoperative condition. When relay I'I operates, however, ground and negative battery l8 are disconnected from the trunk L2 and battery 2| is connected across the trunk L2 in such a manner that the negative bias will be removed from the grid of the tube 20 and it will operate and cause the operation of relay 22. The operation of relay 212 will operate the signal lamp 23. This type of signaling circuit is more completely disclosed in a copending application S. N. 527,9l4, filed March 24, 1944, in the name of C. S. Rhoads. However, it is understood that any desirable arrangement for sig naling over the trunk L2, by means of the actuation of relay I1, may be utilized. When the signal lamp 23 operates an operator atthe master oflice will know that a call has originated either at the master oflice or at the community dial ofiice which must be intercepted because it is for a number not in active use. At the community dial omce a certain unlisted number or numbers will be set aside for the intercept service. For example, let it be assumed that the unlisted number 3425 has 'been'set' aside for this service. Accordingly, when the lamp 23 lights the operator will plug into an idle trunk such as La which will be connected at the community dial ofiice with a selector 24 This will send dialing tone back to the operator at the master allies and she will plug dialing equipment into the jack 25 and commence to dial the number 3425. The first groupof three impulses will cause the switch of selector 24 to move to the third level of contacts and select an idle trunk, such as 26, leading to the connector 21. The next group of four dial impulses will cause the switching mechanism'at the connector to move to the fourth level'of contacts, andthe succeed ing group of two dial impulses will cause it to move to the second terminal thereof, whereupon a connection will be established with the circuit 50. The fourth group of five dial impulses will apply a ringingcode to thecircuit 50. This ringing code will actuate the relay H which in turn will actuate the :relay I3. The actuation of relay I3 will close acircuit 35, includingthe gas-filled discharge tube 33, across thetip and ring conductors of the circuit III-connected to the circuit 9. It will also close a circuit 34 across the circuit 50. These two circuits 34 and 35 will trip the ringing applied to circuits 50 and 9. The operation of relay l3 will cause the operation of relay I4 which will lock up over a connection to the sleeve of circuit 50 which has ground applied to it at connector 21. The operation of relay M will connect. a circuit .Slconnected to the. tip and ring conductors of circuit Soto-the tip and ring conductors of circuit Ill which-tip and ring conductors are connected to the tip and ring conductors of circuit 9.

a talking connection between theoperator at the master station and the subscriberhaving sube scribers set I. The operator at the master ofiice may now inform the subscriber at the set I that the called subscriber having number 2734 cannot be reached at that number and give him the reason therefor.

The arrangements of' the invention may also be used to intercept a call originating in the community dial ofl'ice for the number 2734. A subscriber at the community dial ofifice having a subscribers set 38 might dial the number 2734. In a well-known manner through the line finder 39 the selector 40 and the connector 4|, a connection would be established between the subscriber having set 38 and the circuit 42. This circuit would be connected in multiple with the circuit 9, which as heretofore pointed out, is connected to the circuit I0. Accordingly, when such a connection is established in the same manner as heretofore pointed out, the signal lamp 23 at the master ofiice would light and the operator would then again proceed to dial an unlisted number such as 3425. This would cause the operator to be connected to circuit 50 which in turn is connected to circuits I 0 and 9. As circuit 9 is connected to circuit 42 the operator at the master oflice would then be connected to the subscriber having the set 38 and could inform him that the subscriber having the number 2734 could not be reached at that number.

The arrangements of the invention could also' be used to intercept calls for other lines, such, for example, as lines 9 and 9". These lines would be multipled by circuits 42 and 42" to the connector 4! so that a call for either of these lines could be intercepted whether it originated at the master ofiice or at the community dial ofiice. If the line 9 was a party line and the calls to be intercepted were for a particular party on the line, it would be provided with an intercept trunk 43. A call for a particular subscriber on line 9 would actuate mechanism in the intercept trunk 43' and put a ground on conductor H4. This wouldclose the following circuit: from ground, conductor H4, winding of relay 188, break contact of relay I08, conductor HI, break contact of relay I91, Winding of relay I01 to battery and ground. This would operate relays I08 and I01 and they would lock up over a circuit completed over conductor I I5 to ground applied to the sleeve of line 9' when it was seized by the connector 8.

s It is pointed out that the previously traced circuit for operating relays l 98 and H11 could not be closed if a call was being intercepted on line 9 p because such an interception would have oper- This will establish ated and locked up relay lill. Accordingly. if a call to be intercepted comes in for line 9 while a call is being intercepted on line 9 the intercept apparatus associated with line 9 will not function until after the operator has completed her interception of the call on line 9. As previously pointed out, the operation of rela Ill! places a ground on conductor Hi to operate a signal at the master. oflice. A call to be intercepted coming in for a line such as 9", which is not a party line, would operate relay I06. This in turn would operate relays I09 and I9! to-send a signal to the master office. However, if the operator was intercepting a call on either of lines 9 and 9' when the call came in for line 9 relays I09 and IN would not operate due to the fact that relay I07 had already been operated and locked up. Accordingly, the intercept v apparatus associated with line 9" would not function while the operator was intercepting another call.

In Fig. 2 are shown in detail the arrangements of the intercept trunk 43 which is connected to ascents theline to be intercepted fin caccordance with the arrangements or this invention. If,'rfor example, a=particular party on-"the multi-party 1ine9, such asthe party'having ringing; apparatus49,is to be intercepted, the intercept "trunk 43 will be connectcd to theline-fi in a mannerto be pointed out hereinaften an'd line 9 will also be connected to the circuit 1 l0. Lines runningiout ofcommunity dia'l ofilces usually are multi-party lines and the various partles'are reached by using different ringing codes. One common scheme is to .use' five codes su'ch astwo' short rings, three short "rings, fourishort rings,-one long rin or one long-and one {short ring. Withsuch an arrangementjive parties-could be: rung -from:the .tip side. of the l ne and five-parties could berung from the-ring side of theline. "In-most community dialofllces, ringing is accomplished byza central ringing machine which has a rotatingfishaft on which are mounted code 'interru'pters having various combinations f cams-which close contacts that send out the differentrcode ringing impulses andstalso the ground impulse-thatvstarts' off the. ringing at the. proper time to. make certain-a ringing code will be sent out from the beginning .thereof.- If ringing should "start at any instantea connector "was seized, amutilated *ringing codes"would; result as the-connector might be seized at the instant-that the ringing :machine shaft. was halfv way around in cany revolution. "The-ground pulse which con trols theapparatus so that,the ringing code will start-at iits'tbeginning is'called in gthe-art the ifpick-zupmground. This pick-.up:ground is-applied in Fig. 2 to conductor 45 which goes to'the ringingrmachine'atithe connector where it gets this ground pulse: every: revolution of theringing machine shaft-1 atathe start of each ringing cycle as will-:be pointedzout in more detail hereinafter. The :fourth :"group of impulses dialed operates mechanism at. the connectorwhi'ch; picks rout I the properrcode ringing interrupter and connectsit to thecalled line. besconnected' to: thiscode ringing :interrupterin-a manner to be-pointed out hereinafter. .The-foregoingis-wellrknown in the-art. I I

.Ircalls fori -the-subscriberhavin the ringing apparatus-Mwconnectedto the ring side of..line'-9 are=-to:-be intercepted the-intercept trunk -43 will beconnected to line i 9 in the following manner. Azconductor 54 leading to relay A will be connected to theringside of=.:line -9. -Aconductor 52 willbeconnected tothettip sideof 1ine.9,-and a conductor i3 will be connected to.-the-slecve of line: 9. Conductor 45 to which" will be: applied the pick-pp. ground will be connected to the central ringing machine. The -p0int-55-will.beconnected to the' particular code interrupter 55 at the ringing machine assigned to the subscriber having ringing apparatus whose-incomin calls are to be intercepted. The dialing of the fourth group of impulses willconnect tothe. line 9-this same code interrupteriifi and'will-causethe particular subscribefls code ring to be applied to'the ring side offline 9.

'Theapplication of this: ringing current to the ringside'of line9 will'causerelay' A; which is connected to the ring' side of line '9uby -conduotor 54. to operate. 'Whenithe'1ine '9 wasseized at the connector, ground was 'applied to .ithe sleeve thereof. Accordingly wheni'relayA- :operates the following circuit will "be "closed: from ,:ground connected to the sleeve of circuit 9. conductors53, 56,11, 58, armature59 of relayC and its break contact, conductor 60, winding of relay B, to'battery from ground. The closing of this circuit will The intercept trunk :willalso connect '2 the round 1 originally r zapplied t. to-iathe sleeve .of*:circuit-9.' andltthence'tto conductors 56 and: 6 I" t0 the winding :oftrelaytD *zandto battery and ground,':thereby operating-delay D. T'Bheropto'the relay-A. 'Assoon-as:thishappens theii'elay A will not operate any imore ion the iincoming ringing pulses because 'Lthe codeinterrupter E 5 6" will be applying identic'al pulses'to'thewinding'pi' the community dial i'ofiice with the-voperator" and relay A in opposite:directions. -In other wordsna certain code combinationrof'impulses will be "applied 'to relay A over conductor 5 54 from lthe"con-f nector, and an identical set or pulseswil1 be"ap= plied to the winding of relay 'A'over conductor 1'! by the code interrupter '56. "-Wh'en the cr'IeXt "pick-up pulse occurs to "starta 1 second set -o'f ringing impulses, ground wi1l= be applied to: con ductor and thencewovertheaiollowing.circuit: armature 12 and contact of relay D; conduetor wl armature M and contactofxrelay' C; 'conductor =15; winding of relay E to'battery -and-ground, thereby operatin relay E. The peration of relay E will connect the ground'wgwhich is'connected to'con ductor 11; to the conductor I 6 and'thereby-"ca'use the relay I1 of Fig; 'lnto operate-totransmita signal" to the master ofiice in a manner theretofore-explained with respect tofFig; 1. 1 In response to this signal, the operatoratithemaster oilice will dial the unlisted 'number' and-the connector 2101-Fig; 1 win seize the circuit In*-a"manner explained with with respect' to Fig. '1'; zthe 1 operator may =now communicate witli the calling subscriber 'over circuits' 5B," llland-" d to' tell him the reason for intercepting-his'call. I

From the foregoing it -will be {seen that a relay A in the intercept trunki will respond to theifirst impulses in the combination of "impulses consti tuting the code "ring for thesubscr-iber to be iintercepted. This will set other relay mechanism in operation so that when-the next ".pick-up pulse is received at the intercept trunk aground willbe put on conductor Hi to operate-asignal' at the master office' whereupmr thegoperatorthereat will dial the unlisted number" set aside for" intercepting "calls. .Thiswill' establish:'a'connecti'on'at the lineito which is connected the subscriber to be intercepted. 'The code interrupter at'the connector which is also conn'ectedtothe intercept trunk-will be sending identical ringing pulses "to the firstementionedrelayeA in opposite directions audit will fno longer operate after: thefirst ring ingx'pulse' has ended. I I I Forarcall for=on'e-ot'theother parties on the line 9 which is not to be intercepted. th code ring received from. the'connector which: seizes 11116 9 w'ill'no't bethe same as the code ring connected to point55. Such a. call may beeither one that puts theringing pulses outon the tip of line 9- or on therringi thereof 'If the impulses :are applied" to thextip ltheyawill immediately operate 'relayG which is connected to the tip of the line by conduct0r52. The operation of relay G willoperate operatea relayllBs "lheloperatlon of relayl'B will the relay H by connecting its winding over con ductor 53 to ground placed on the sleeve of circuit 9. This holds Open the circuit for relay A. This cancels any further action and hence, there is no further interferenceand no interception.

- If any other code combinations are transmitted out over the ring side of the line other than the one to be intercepted, the first of these pulses will operate the relay A. I The operation ofrelay A will cause relay C to operate and lock upin the same manner as previously described. The operation of relay C closes a circuit from the ringin interrupter 55 as follows: cnnductors'fidi'l, 68, make contact and armature B9 of relay-C, conductors and H to the winding of relay A. When the next impulse in the ringing code, which comes from some cam other than on interrupter 56', is applied to the ring side of the line, it will be transmitted through the winding of-relay A and over said last-mentioned circuit to ground associated either with battery Hill or battery NH. Because the ringing codes do not match, this will cause relay A to operate on the second of the pulses of the code combination. 'When relay -A operates a second time the following circuit will be completed: from ground connected to sleeve of line 9 and thence to conductor 51, over'corn ductor 58, armature 59 and make contact of relay 0, conductor' I04, contact and armature Hi5 of relay D, conductor I 06', winding of relay H to battery and ground. 'This will operate relay H whichwill lock up-and open the operating circuit of relay A. Accordingly, relay A will not operate on succeeeding code impulses. This cancels any further action and hence there is no further interference and no interception of the other parties on the same side of the line.

While the arrangements of the intercepted trunk have been shown as adapted to intercept a party connected to the ring side of the line, they may be utilized to intercept a party connected to the tip side of the line by merely connecting conductor 54 to the tip side of the line and connecting conductor 52 to the ring side of the line. While the arrangements'of the invention'have been disclosed as having been embodied in certain specific forms which are described, it-is understood that they are capable of embodiment in many and widely varied forms without departing from the spirit of the invention as defined by the appended claims. a

What is claimed'is: '1. A telephone system including an unattended exchange having two connectors, amulti-part telephone line on which incoming calls for aparticular one of the parties on the line are to be intercepted, meansfor connecting saidline to a terminal in one of'said connectors which terminal'might be reached by'dialin'g a designated number, means for connecting aid line to a terminal in the other connector which terminal might be reached by dialing another designated number, and means connected to said telephone line and responsive only to the particular code signal for the party whose calls are to be inter cepted for transmitting a signal to an attended exchange.

2. A telephone system including an unattended exchange having two connectors, a multi-party telephone line on which incoming calls for aparticular one of the parties on the line are to be intercepted, means for connecting said line toa terminal in one of said connectors which terminal might be reached by'dialing a designated-humber, means for connecting said line to a terminal in the other connector which terminal might be reached by dialing another designated numher, an intercept trunk associated with said line, said intercept trunk including apparatus selectively responsive to the codesignal individual to the particular party whose calls are to be inter cepted, and means controlled by said apparatus for transmitting a signal to an attended ex change. a 3. A telephone system including an unattended exchange having two connectors, a multi-party telephone line on which incoming calls for a particular one of the parties on the line are tobc intercepted, means for connecting said line to a terminal in one of said connectors Whichterminal might be reached by dialing a designated number, means for connecting said line to a ter: minal in the other connector which terminal might be reached by dialing another designated number, an intercept trunk associated with said line, said intercept trunk including apparatus responsive when the code signal individual to the particular party whose calls are to be intercepted is applied to said line, signaling means controlled by said responsive apparatus for transmitting a signal 'to'an attended exchange, said intercept trunk also including apparatus responsive when a code signal other than said first mentioned code signal is applied to ,said line, and means controlled by said last mentioned responsive apparatus for preventing said signaling means from operating.

4. A telephonesystem including an unattended exchange having two connectors, a telephone line on which incoming calls are to be intercepted, means for connecting said line to a terminal in one of said connectors which terminal might "be reached by dialing a first number, a second' telephone line on which incoming calls areto be intercepted, means for connecting said line to another terminal in said last mentioned connector which terminal might be reached by dialing a second number, means for connecting both of said lines to the same terminal in the'other connector which terminal might'be reached by dialing a third number, responsive meansasso'-' ciated with said first line and operative when said first number is dialed for transmitting a signal to an attended exchange, responsive means as sociated with said second line and operative when said second number is dialed for transmitting a signal to an attended exchange, and means operative when said first mentioned responsive means is operated for preventing said second mentioned responsive means from operating to transmit said Signal- I I 1.. 5. A telephone system including a pluralityzof lines at an exchange, a signaling circuit common to all of said lines for transmitting a signal to another exchange, a relay controlling said signaling circuit, relays individual to each or said lines and each being responsive to signals coming in over its associated line, and a plurality of operating and locking circuits for said first relay each completed over the contacts of different ones of aid individual relays whereby when said first relay is operated and locked up b the operation of one of said individual relays it will be unaf-= fected by the operation of another of said individual relays. v i

CHARLES STANLEY RHOADS .Y{;' 

